Stream line hollow spar or strut for aircraft



UNITED STATES PATEN T OFFICE.

FREDERICK.HANDLEY PAGE, OF LONDON, ENGLANE'ASSIGNOR '10 HANDLEY PAGELIMITED, or LONDON, ENGLAND.

I STREAM-LINE HOLLOW SPAR R STRUT FOR AIRCRAFT.

Specification of Letters Patent.

Patented Sept. 23, 1919.

Application filed May 26, 1919. Serial No. 300,002.

To all whom it may concern:

Be it known that I, FREDERICK HANpLnY PAGE, a subject of the King ofGreatBritain, residing at London, England, have lnvented certain new anduseful Improvements in Stream-Line Hollow Spars or Struts for Aircraft,of which the following is a speclfication.

Hollow spars have before been constructed .0 of separate lengths of woodhollowed out and joined longitudinally and these have been made invarious forms and cross sec- :tions. In all cases however the materialforming the spar has been shaped to accom- 5 modate not only theexternal form required but to satisfy the resistance to strains andshock to which the spar is to be subjected.

According to this invention the spar is first constructedin a form mostsuitable for 0 the strains which it is to receive and the spar thusconstructed is then fitted with external fairings at the leading andtrailing portions of the spar, the fairings being made as, light aspossible in view of the fact that 5 they are required to resist windforce only and are not strain.

In the .accompanying sheet of drawings a strut suitable for connectionbetween the required to take any of the 0 upper and lower wings of anaeroplane is illustrated, Figure 1 being an external side view of oneend of such a strut and Fig. 2 a front view of the same. Fig. 3 is across section drawn to a larger scale than the pre- 5 vious figures.

The material forming the strain bearing portion of the strut is shown intwo pieces 1 and 2 joined together longitudinally, the two oppositefaces of the parts 1 and 2 be- 0 ing suitably grooved to receive afeather 3 by which they are firmly keyed together. Slmllar joints aremade on all abutting faces of the strut sections and when these jointshave been effectively made, a hollow strut 5 is produced ofapproximately rectangular form and which although extremely strong wouldolfer considerable resistance when forced through the air in flight.

The exterior is therefore shaped to enable fairings to be attached,which, when joined rior of the fairing can be bent and by the formers 4be caused to assume the shape re quired. As shown in Fig. 3 the formers4 may be of skeleton form. 4

The thin material 5 at the edges where it joins to the strut section 1is received in recesses 6 so as to make its external form continuouswith the strain bearing portion of the strut. This thin material 5 ispreferably formed of single'ply wood, the grain running longitudinallyof the strut and it has been found that this material assumes therequired form more perfectly than other materials.

The trailing fairing is constructed in a somewhat simllar way on formers7, the thin tion of the strut. In this case however owing to the moreacute angle of the trailing edge of the fairing, the thin material 8 isapplied in two portions joined together at the extreme trailing edge 10where it is supported on the interior by a longitudinal strip 11 held inrecesses 12 situated in the formers 7.

The struts constructed in accordance with this invention are onlyprovided with fairings through the greater portions of their lengths,the said fairings being reduced and tapered down to meet the strainbearing portion of the strut so as to leave the ends of the strainbearing portion projecting, to facilitate fitting to the wings or otherparts of the machine.

Taper blocks 13 are attached on the for.- ward and trailing edges of thesolid projecting portions of the strut, where the fairing commences inorder to form a seat for the reception of the thin material and to makea good joint and a firm connection with the strain bearing portion ofthe strut.

What I claim as my invention and desire to secure by Letters Patentis 1. A hollow spar built up of strain hearing portions designed forreceiving strain only, combined with wind fairing portions comprisingtransverse skeleton formers supporting and shaping thin sheathingdesigned for reducing the wind resistance on y.

2. A hollow spar or strut comprising a built up strain bearing memberhaving solid ends in combination with a wind, fairing casing at theleading edge and a wind fairing casing at the trailing edge, said windmaterial 8 being received in recesses 9 in fairing casings comprising aplurality of formers and a sheathing, each secured to the strain bearingmember for the majority of its length and tapering at each end in orderto leave the solid ends of the strain bearing member exposed.

3. A hollow spar or strut.comprising a built up strain bearing member,in combination with a series of formers secured to the leading andtrailing edges of the said strain bearing member and projecting at rightangles therefrom and coverings or fairings around said formers securedto the sides of the strain bearing member, the whole forming a strut ofstreamline form.

4. A hollow spar or strut comprising a built up strain bearing member,in combination with a series of formers secured to the leading andtrailing edges of the strain bearing member and projecting at rightangles therefrom, a covering of single ply wood, with the grainlongitudinal of the spar or strut, bent around said formers on theleading edge of the strain bearing member and secured at its edges tothe sides of the said member and a cover of thin material around saidformers on the trailing edge the whole forming a strut of streamlineform.

5. A hollow spar or strut comprising a built up strain bearing member,in combination with a series of formers secured to the leading andtrailing edges of the strain bearing member and projecting at rightangles therefrom, a covering of single ply Wood, with the grainlongitudinal of the spar or strut, bent aroundthe formers on the leadingedge of the strain bearing member and secured at its edges to the sidesof the'said member, a longitudinal strip supported by the formers on thetrailing edge of the strain bearing member and two coverings attached toone side of said longitudinal strip and to the sides of the strainbearing member, the whole forming a strut of streamline form.

6. In an aircraft spar, the combination of a strain bearing member, askeleton frame having lateral formers, attached thereto, and a thinsheathing covering said frame to produce a streamline form.

In witness whereof I have hereunto set my hand in the presence of twowitnesses.

FREDERICK HANDLEY PAGE.

